The esophagus is a tubular muscular organ having a length of approximately 25 cm, located between the upper esophageal sphincter (UES) and the lower esophageal sphincter (LES). The esophagus functions solely to deliver food from the mouth to the stomach using peristaltic muscle motion. Peristalsis is a sequential, coordinated contraction wave that travels the entire length of the esophagus, propelling intraluminal contents distally to the stomach. Primary peristalsis is the peristaltic wave triggered by the swallowing center. The peristaltic contraction wave travels at a speed of approximately 2 cm/s and correlates with manometry-recorded contractions. The secondary peristaltic wave is induced by esophageal distension from the retained bolus, refluxed material, or swallowed air, with the primary role to clear the esophagus of retained food or any gastroesophageal refluxate. Tertiary contractions are simultaneous, isolated, dysfunctional contractions. Anesthetization or sedation are suspected of causing suspension of esophageal peristaltic motility and lowers LES pressure, hence gastric content are more prone to infiltrate and travel proximally in the esophagus.
Gastric contents refluxing through the esophagus are known to affect conditions which may increase morbidity and mortality rates. Gastroesophageal Reflux (GER) is a condition, in which the LES opens spontaneously, for varying periods of time, or does not close properly and stomach contents rise up into the esophagus. In Laryngopharyngeal Reflux (LPR), the retrograde flow of gastric contents reaches the upper aero-digestive tract. In order to diminish and treat such conditions, efforts have been made to develop medical and surgical means for improving LES functionality and for creating a substitute sphincter proximally adjacent the stomach. In some occasions it may be advantageous to develop a second “line of defense” provided proximally to the LES along the esophagus, especially to push back any gastric contents or chyme that infiltrated the LES or any substitute or supplement thereof. Such a need may arise, for example, in cases of intubation and/or ventilation, usually in anesthetized ICU patients, CVA patients, or others, in which esophageal motility is muted or less dominant.
Tube feeding (e.g., gastric feeding, or enteral feeding) is a common and life preserving procedure, however, complications can arise. GER is commonly associated with tube feeding, including in usage of nasogastric tubing (NGT) and other gastric feeding practices. Research in past years has discussed the emergence of GER as an effect of the use of NGT, for example, as disclosed in Ibanez et al., “Gastroesophageal reflux in intubated patients receiving enteral nutrition: effect of supine and semirecumbent positions”, JPEN J Parenter Enteral Nutr. 1992 September-October; 16(5):419-22; in Manning et al., “Nasogastric intubation causes gastroesophageal reflux in patients undergoing elective laparotomy”, Surgery. 2001 November; 130(5):788-91 and in Lee et al., “Changes in gastroesophageal reflux in patients with nasogastric tube followed by percutaneous endoscopic gastrostomy”, J Formos Med Assoc. 2011 February; 110(2):115-9.
Pulmonary aspiration is the entry of material from the oropharynx or gastrointestinal tract into the larynx and lower respiratory tract. Consequences of pulmonary aspiration range from no injury at all, to chemical pneumonitis or pneumonia, to death within minutes from asphyxiation. One common cause of pulmonary aspiration is aspiration of gastric contents, as suggested in relevant literature, for example. Pellegrini el al., “Gastroesophageal reflux and pulmonary aspiration: incidence, functional abnormality, and results of surgical therapy”. Surgery. 1979 July; 86(1):110-9, indicating that incidence of aspiration is due to a motor disorder that interferes with the ability of the esophagus to clear refluxed acid, and that abnormal pulmonary symptoms can induce or result from gastroesophageal reflux.
Ventilator-associated pneumonia (VAP) is pneumonia that develops 48 hours or longer after mechanical ventilation is given by means of an endotracheal tube or tracheostomy. VAP results from the invasion of microorganisms into the lower respiratory tract and lung parenchyma. Intubation compromises the integrity of the oropharynx and trachea and allows oral and gastric secretions to enter the lower airways. The aetiopathogenesis of VAP requires abnormal oropharyngeal and gastric colonization and the further aspiration of their contents to the lower airways. Known risk factors for gastric colonization include: alterations in gastric juice secretion; alkalinization of gastric contents; administration of enteral nutrition; administration of antacids; and the presence of bilirubin. According to Torres et al. (in “Stomach as a source of colonization of the respiratory tract during mechanical ventilation: association with ventilator-associated pneumonia”, Eur Respir J. 1996 August; 9(8):1729-35), although the role of the colonized gastric reservoir in the development of VAP remains debatable, there is major evidence in the literature in favor of the gastric origin of part of these pulmonary infections.
US Patent Appln. Publication No. 2011/0130650 A1 relates to an enteral feeding device comprising “expandable means which prevents or significantly reduces aspirations from the alimentary tract to the respiratory system. In further aspects, the invention relates to systems comprising said enteral feeding device, methods and uses thereof.”.
US Patent Appln. Publication No. 2010/0160996 A1 relates to methods and apparatuses for treating ailments by “inserting a balloon-electrode device into an esophagus of a mammal, the balloon-electrode device including: (i) a nasogastral (NG) tube having an internal passageway and an external surface, (ii) at least one electrode coupled to the external surface of the NG tube, (iii) a conductor extending through the internal passageway of the NG tube and electrically connecting to the electrode, and (iv) a balloon surrounding the electrode and a portion of the NG tube; inflating the balloon with fluid such that the electrode is substantially centrally located within an interior volume of the balloon; and applying at least one electrical signal to the electrode via the conductor such that an electromagnetic field emanates from the electrode to at least one of nerves and muscles of the mammal”.
US Patent Appln. Publication No. 2008/0249507 A1 relates to a “food administering apparatus including a feeding tube, having a distal outlet and proximal inlet, adapted for insertion of the distal outlet into the stomach of an adult patient while the proximal inlet is outside the patient, the tube being suitable for administering food or medicine from a proximal port to the distal outlet and at least one electrode mounted on the tube”.
US Patent Appln. Publication No. 2008/0319504 A1 relates to a “device for stimulating select body tissues and organs from within a compartment in a body. The device includes a tube and at least one distendable element configured to expand against the compartment into a first position and contract within the compartment into a second position. At least one electrical component is in association with each of the distendable elements and configured to activate and deactivate electrical stimulation to the select body tissues and organs. The expansion and contraction of each distendable element and the activation and deactivation of each electrical component in the compartment is repeated over a period of time.”.
The same applicant/assignee of the present disclosure developed techniques for generating motility in a subject's gastrointestinal (GI) tract and organs thereof, including, for example, techniques for generating esophageal motility in a subject. Exemplary teachings and practices of such techniques are provided in same applicant/assignee disclosures: U.S. Patent Appln. Publication No. US 2013/0006323 A1, and PCT Int'l. Patent Appln. Publication No. WO 2014/105759 A1.
In spite of such teachings in the field of the invention, there is an on-going need for developing and practicing improved or/and new techniques for generating esophageal motility in a subject's gastrointestinal (GI) tract.